Electrode and Secondary Battery

The present application claims priority to and the benefit of Korean Patent Application No. 10-2024-0100780, filed on Jul. 30, 2024, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.

The present disclosure relates to an electrode and a secondary battery.

Secondary batteries are batteries that can be charged and discharged, unlike primary batteries that cannot be recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor driving in hybrid vehicles, electric vehicles, and the like, and batteries for power storage, or the like. These secondary batteries include electrodes including a positive electrode and/or a negative electrode, an electrode assembly including the electrodes, a case accommodating the electrode assembly, an electrode terminal connected to the electrode assembly, and the like.

The electrode includes a substrate and a coating layer formed on the substrate. The coating layer includes an active material. In addition, the electrode includes a tab attached to the substrate. The electrode assembly including such an electrode may be, for example, wound to form a jelly roll.

The above-described with respect to formation disclosed in the background technology of the disclosure is only intended to provide a better understanding of the background of the present disclosure, and therefore information that does not constitute the related art may be included.

Embodiments include an electrode, including a substrate, a tab having a first side joined to one surface of the substrate and a second side extending away from the substrate, the first side and the second side being opposite each other along a longitudinal direction of the tab, and a metal layer on the substrate and covering at least a portion of the tab, the metal layer including a metallic material.

The metal layer may be joined to the substrate by a welded portion.

The welded portion may be spaced a predetermined distance apart from the tab and is parallel to the tab.

The metal layer and the substrate may include a same material.

The substrate may include aluminum, and the metal layer may include aluminum, a metal coated with aluminum, aluminum coated with another material, or an alloy including aluminum.

The substrate may include copper, and the metal layer may include copper, a metal coated with copper, copper coated with another material, or an alloy including copper.

The substrate may include copper, and the metal layer may include at least one of iron, stainless steel, nickel, gold, silver and a combination thereof.

In a cross-section of the tab perpendicular to a longitudinal direction of the tab, the metal layer may include a tab cover layer corresponding to a shape of the tab, the tab cover layer surrounding the tab, and a substrate cover layer extending from the tab cover layer, the substrate cover layer being on the substrate.

The electrode may further include an additional metal layer on another surface of the substrate, the additional metal layer including a metallic material.

The electrode may further include an active material layer on a part of another surface of the substrate, wherein the tab is joined on the one surface of the substrate without the active material layer, and the metal layer does not cover the active material layer.

Embodiments include a secondary battery, including an electrode assembly in which an electrode and a separator are alternately stacked, and a case in which the electrode assembly is accommodated, and wherein the electrode includes a substrate, a tab having a first side joined to one surface of the substrate and a second side extending away from the substrate, the first side and the second side being opposite each other along a longitudinal direction of the tab, and a metal layer on the substrate and covering at least a portion of the tab, the metal layer including a metallic material.

The metal layer may be joined to the substrate by a welded portion.

The welded portion may be spaced a predetermined distance apart from the tab, the welded portion being parallel to the tab.

The metal layer and the substrate may include a same material.

The substrate may include aluminum, and the metal layer may include one of aluminum, a metal coated with aluminum, aluminum coated with another material, and an alloy containing aluminum.

The substrate may include copper, and the metal layer may include one of copper, a metal coated with copper, copper coated with another material, and an alloy containing copper.

The substrate may include copper, and the metal layer may include at least one of iron, stainless steel, nickel, gold and silver.

In a cross-section of the tab perpendicular to a longitudinal direction of the tab, the metal layer may include a tab cover layer corresponding to a shape of the tab, the tab cover layer surrounding the tab, and a substrate cover layer extending from the tab cover layer, the substrate cover layer being on the substrate.

The electrode assembly may include a winding with a curvature, and the metal layer may be bent with the curvature.

The electrode may include an additional metal layer on another surface of the substrate, the additional metal layer including a metallic material.

Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.

Hereinafter, embodiments of the present disclosure will be described, in detail with reference to the accompanying drawings. The terms or words used in the present specification and claims are not to be limitedly interpreted as general or dictionary meanings and should be interpreted as meanings and concepts that are consistent with the technical idea of the present disclosure on the basis of the principle that an inventor can be his/her own lexicographer to appropriately define concepts of terms to describe his/her disclosure in the best way. Therefore, the embodiments described with respect to this specification and the configurations shown in the drawings are only some of one or more embodiments of the present disclosure and do not represent all of the aspects of the present disclosure. Accordingly, it should be understood that there may be various equivalents and modifications that can replace or modify one or more embodiments described herein at the time of filing this application.

In addition, when used in the present specification, “comprise” and “include” and/or “comprising” and “including” specify the presence of stated features, numbers, steps, operations, members, elements, and/or groups thereof and do not preclude the presence or addition of one or more other features, numbers, steps, operations, members, elements, and/or groups.

In addition, to aid understanding of the disclosure, the accompanying drawings may not be shown to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be assigned to the same components in different embodiments.

The statement that two comparative objects are ‘identical’ means they are ‘substantially identical’. Therefore, substantially identical may include a case that have a deviation considered low in the industry, for example, a deviation of less than 5%. In addition, the indication that a certain parameter is uniform in a predetermined area may mean uniform from an average perspective.

Although first, second, and the like are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are only used to distinguish one component from another component, and unless otherwise stated, it goes without saying that the first component may be the second component.

Throughout the specification, unless otherwise stated, each component may be singular or plural.

The placement of an arbitrary component on the “upper portion (or lower portion)” of a component or “above (or below)” of a component may mean not only that the arbitrary component is disposed in contact with an upper surface (or a lower surface) of the component, but also that another component may be interposed between the component and the arbitrary component disposed above (or below) the component.

In addition, when a first component is described as being “connected,” “coupled,” or “joined” to a second component, the components may be directly connected or joined, but it should be understood that a third component may be “interposed” between the components, or the components may be “connected,” “coupled,” or “joined” through the third component. In addition, when a first component is described as being “electrically coupled to” a second component, this includes not only a case in which the first component is “directly coupled” to the second component, but also a case in which the first component is “coupled” to the second component with a third component interposed therebetween.

When referring to “A and/or B” throughout the specification, this means A, B, or A and B unless otherwise specified. In other words, the term “and/or” includes all or any combination of the plurality of listed items. When referring to “C to D,” this means C or more and D or less unless otherwise specified.

The terminology used in the present application is for the purpose of describing embodiments of the present disclosure and is not intended to limit the present disclosure.

1 FIG. is a cross-sectional view schematically showing a cylindrical secondary battery according to an embodiment of the present disclosure.

1 FIG. 100 50 40 60 100 100 60 60 As shown in, a secondary battery(of the cylindrical, lithium-ion type) according to an embodiment of the present disclosure may include a cylindrical case, an electrode assembly, and a cap assembly. In addition, the secondary battery(of the cylindrical, lithium-ion type) may further include a center pin in some embodiments. Also, in the secondary batteryaccording to an embodiment of the present disclosure, since the cap assemblyalso performs a current interrupt operation, the cap assemblymay be referred to as a current interrupt device in some cases.

50 50 40 50 50 The cylindrical casemay include a substantially circular bottom portion and a cylindrical side wall that upwardly extends a predetermined length from the circumference of the bottom portion. During the manufacturing process of the secondary battery, an upper portion of the cylindrical caseis open. Therefore, during the assembly process of the secondary battery, the electrode assemblyand the center pin may be inserted into the cylindrical casealong with an electrolyte. The cylindrical casemay be made of, for example, steel, stainless steel, aluminum, an aluminum alloy, or an equivalent thereof, but the material of the case may vary.

40 50 40 20 10 30 20 10 20 10 30 2 2 4 The electrode assemblymay be accommodated inside the cylindrical case. The electrode assemblymay include a negative electrodein which a negative electrode active material (for example, graphite, carbon, etc.) is coated on a negative electrode current collector plate, a positive electrodein which a positive electrode active material (for example, a transition metal oxide (LiCoO2, LiNiO, LiMnO, etc.)) is coated on a positive electrode current collector plate, and a separatorlocated between the negative electrodeand the positive electrodeto prevent a short circuit and allow only the movement of lithium ions. In addition, the negative electrode, the positive electrode, and the separatormay be wound in a substantially cylindrical shape.

60 60 60 50 40 50 The cap assemblyincludes a cap-up. The cap assemblymay further include at least one of a cap-down, a vent, and an insulator. The cap assemblymay be coupled to an opening of the cylindrical caseso that the electrode assemblyis sealed inside the case.

However, the case may be formed in any of various shapes such as a circular shape or a pouch shape. In addition, the case may be made of a metal, such as aluminum, an aluminum alloy, or nickel-plated steel, or a laminated film or plastic that forms a pouch.

40 20 10 30 20 10 40 50 40 Meanwhile, as described above, the electrode assemblymay include the negative electrode, the positive electrode, and the separatorlocated between the negative electrodeand the positive electrode. In addition, the electrode assemblyis accommodated in the cylindrical casealong with the electrolyte. Hereafter, the electrode assemblyand the electrolyte will be described.

As the positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) may be used. Specifically, at least one of composite oxides of a metal selected from cobalt, manganese, nickel, a combination thereof and lithium may be used as the positive electrode active material.

The composite oxide may be a lithium transition metal composite oxide, and specific examples may include a lithium nickel oxide, a lithium cobalt oxide, a lithium manganese oxide, a lithium iron phosphate compound, a cobalt-free nickel-manganese oxide, or a combination thereof.

a l-b b 2-c c a 2-b b 4-c c a l-b-c b c 2-α α a il-b-c b c 2-α α a b c d 2 a b 2 a b 2 a l-b b 2 a 2 b 4 a l-g g 4 (3-f) 2 4 3 a 4 l As an example, a compound represented by any of the following formulas may be used: LiAXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiMnXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiNiCOXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiNMnXOD(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0 <α<2); LiNiCoLGeO(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiNiGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiCoGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGO(0.90≤a≤1.8, 0.001≤b≤0.1); LiMnGPO(0.90≤a≤1.8, 0≤g≤0.5); LiFe(PO)(0≤f≤2); and LiFePO(0.90≤a≤1.8).

In the above chemical formulas, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L is Mn, Al, or a combination thereof.

10 100 The positive electrodefor the secondary batterymay include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include the positive electrode active material, and may further include a binder and/or a conductive material.

The content of the positive electrode active material may range from 90 wt % to 99.5 wt % based on 100 wt % of the positive electrode active material layer, and the contents of the binder and the conductive material may each range from 0.5 wt % to 5 wt % based on 100 wt % of the positive electrode active material layer.

Al may be used as the current collector, but the material of the current collector may vary.

The negative electrode active material may include a material capable of reversible intercalation/deintercalation of lithium ions, lithium metal, an alloy of lithium and a metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

The material capable of reversible intercalation/deintercalation of lithium ions may be a carbon negative electrode active material, which may include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon may include graphite, such as natural graphite or artificial graphite, and examples of the amorphous carbon may include soft carbon, hard carbon, pitch carbide, mesophase pitch carbide, calcined coke, and the like.

x As the material capable of doping and dedoping lithium, a Si negative electrode active material or a Sn negative electrode active material may be used. The Si negative electrode active material may be silicon, a silicon-carbon composite, SiO(0<x<2), a Si alloy, or a combination thereof.

The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to an embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on surfaces of the silicon particles.

The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

20 100 The negative electrodefor the secondary battery(e.g., lithium) may include a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer may include the negative electrode active material and may further include a binder and/or a conductive material.

For example, the negative electrode active material layer may include 90 wt % to 99 wt % of the negative electrode active material, 0.5 wt % to 5 wt % of the binder, and 0 wt % to 5 wt % of the conductive material.

A non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used as the binder. When the aqueous binder is used as the negative electrode binder, a cellulose compound may be further included to impart viscosity.

As the negative electrode current collector, one selected from a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a conductive metal-coated polymer substrate, and a combination thereof may be used.

100 The electrolyte for the secondary battery(e.g., lithium) may include a non-aqueous organic solvent and a lithium salt.

The non-aqueous organic solvent may serve as a medium through which ions involved in the electrochemical reaction of the battery may move.

The non-aqueous organic solvent may be a carbonate, ester, ether, ketone, or alcohol solvent, an aprotic solvent, or a combination thereof, and may be used alone or in combination of two or more.

In addition, when using the carbonate solvent, a mixture of a cyclic carbonate and a chain carbonate may be used.

100 30 10 20 30 Depending on the type of secondary battery(e.g., lithium), the separatormay be present between the positive electrodeand the negative electrode. As the separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.

30 The separatormay include a porous substrate and a coating layer containing an organic material, an inorganic material, or a combination thereof located on one surface or both surfaces of the porous substrate.

The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

2 3 2 2 2 2 2 2 3 3 3 2 The inorganic material may include inorganic particles selected from AlO, SiO, TiO, SnO, CeO, MgO, NiO, CaO, GaO, ZnO, ZrO, YO, SrTiO, BaTiO, Mg(OH), boehmite, and a combination thereof, but may vary.

The organic material and the inorganic material may be present as a mixture in one coating layer or may be present in a form in which a coating layer containing an organic material and a coating layer containing an inorganic material are stacked.

2 FIG. 200 is a cross-sectional view schematically showing an electrodeaccording to an embodiment of the present disclosure.

200 210 230 210 210 230 240 210 230 The electrodeincludes a substrate, a tabhaving one side joined to one surface of the substrateand the other side (e.g., a second side) extending from the substrate(e.g., a first side of the tabjoined to one surface of the substrate and a second side extending away from the substrate, the first side and the second side being opposite each other along a longitudinal direction of the tab), and a metal layerprovided on the substratewhile covering at least a portion of the taband including a metallic material.

200 210 200 210 200 With this configuration, the electrodecan prevent cracks from occurring in the substrate. In addition, the electrodecan maintain electrical conductivity even when cracks occur in the substrate. Hereinafter, each of the components of the electrodewill be described with respect to detail.

200 10 20 40 10 20 10 40 200 20 40 200 10 20 40 200 1 FIG. The electrodemay include a positive electrodeand/or a negative electrode. For example, as described with respect to, the electrode assemblyaccording to an embodiment of the present disclosure may include the positive electrodeand the negative electrode. In this case, the positive electrodeincluded in the electrode assemblymay be applied as the electrodeaccording to an embodiment of the present disclosure. In this case, the negative electrodeincluded in the electrode assemblymay be applied as the electrodeaccording to an embodiment of the present disclosure. Furthermore, the positive electrodeand the negative electrodeincluded in the electrode assemblymay be applied as the electrodeaccording to an embodiment of the present disclosure.

200 210 220 210 The electrodemay include the substrateand a coating layerprovided on a portion of the substrate.

210 200 10 210 200 20 210 1 FIG. The substratemay include the current collector described with respect to. For example, when the electrodeis the positive electrode, the substratemay include a positive electrode current collector. The positive electrode current collector may include, for example, aluminum (Al). When the electrodeis the negative electrode, the substratemay include a negative electrode current collector. The negative electrode current collector may include, for example, copper (Cu).

220 200 10 200 20 220 1 FIG. The coating layermay include an active material, e.g., the active material layer described with respect to. When the electrodeis the positive electrode, the active material may include a positive electrode active material. When the electrodeis the negative electrode, the active material may include a negative electrode active material. In addition, the coating layermay further include a binder and/or a conductive material.

220 210 220 210 The coating layermay be applied on the substratein the form of a slurry including the active material. In other embodiments, the coating layermay be attached to the substratein the form of a freestanding film including the active material.

220 210 220 210 220 210 220 210 210 220 210 2 FIG. In this case, the coating layermay be provided on a portion of the substrate. For example, the coating layermay be provided on a portion of one surface of the substrate. In other embodiments, for example, as shown in, the coating layermay be provided on portions of both surfaces of the substrate. In this case, a region in which the coating layeris provided on a portion of the substratemay be referred to as a coated portion for convenience. In addition, as the other portion of the substrate, a region in which the coating layeris not provided and the substrateis exposed to the outside may be referred to as an uncoated portion for convenience.

200 230 210 230 210 230 230 210 210 The electrodemay include the tabattached to the substrate. The tabmay have one side attached to the substrate. The tabmay extend from one side toward the other side. Accordingly, the other side of the tabmay not be attached to the substrateand may be formed by extending outward from the substrate.

2 FIG. 2 FIG. 230 220 230 230 230 210 230 210 For example, as shown in, the tabmay include a middle tab in which the coating layeris provided at both sides of the tab. In other embodiments, for example, the tabmay include a case in which the tabis attached to an end portion of the substrate, unlike as shown in. In this way, the tabmay include any type of tab in which at least one side thereof is provided on the substrate.

230 200 230 230 200 230 200 230 The tabmay provide a passage through which the electrodemay be electrically connected to the outside. To this end, the tabmay include a conductive material. For example, the tabmay include a metallic material. Therefore, electrons may move to the electrodealong the tabor from the electrodeto the outside through the tab.

230 210 230 210 230 230 210 The tabmay be attached to the substrate. For example, the tabmay be attached to the substratethrough a conductive tape or an adhesive material. In other embodiments, when the tabincludes a metallic material, the tabmay be attached to the substratethrough welding.

200 230 100 200 210 210 230 210 210 As described above, the electrodemay include the tab. In this case, as the secondary batteryperforms charging/discharging or deteriorates, the electrodemay repeatedly expand and contract. The substratemay be pressed by the separator and/or the electrode located in front of and behind the substrate. In particular, a tab boundary portion, which is a region where the tabis attached in the substrate, may be more strongly pressed. In this case, cracks may occur in the substrate.

200 240 210 230 240 210 240 210 In order to solve this problem, the electrodeaccording to an embodiment of the present disclosure may include the metal layerprovided on the substratewhile covering the tab. Therefore, the metal layercan reinforce the mechanical strength of the substrate. In addition, the metal layercan prevent cracks from occurring in the substrate.

240 210 230 220 240 240 210 220 Meanwhile, the metal layermay be formed on the substratewhile covering the tab, but may be provided so as not to cover the coating layer. That is, the metal layermay be located only on the uncoated portion and may not be located on the coated portion. Therefore, the metal layermay reinforce the strength of the substratewhile preventing the problem of increased resistance or decreased capacity by blocking the coating layer.

240 210 240 240 210 200 The metal layermay include a metallic material. In this case, the metallic material may include any conductive material through which electrons can move. Therefore, even when cracks occur in the substrate, the metal layermay allow electrons to move through the metal layerprovided on the substrate. Accordingly, the reliability of the electrodecan be improved.

200 50 210 230 230 210 240 240 210 240 210 240 240 210 240 230 210 240 230 210 w. Meanwhile, the electrodeaccommodated in the cylindrical casemay be generally bent to form a jelly roll. In this case, even when a reinforcing tape is attached to the substratewhile covering the tab, the tape may be lifted at a boundary region between the taband the substrate. Accordingly, there is a problem that cracks may occur in a region in which the tape is lifted. In contrast, since the metal layeraccording to an embodiment of the present disclosure includes a metallic material, the metal layermay be joined to the substratethrough welding. That is, the metal layermay be joined to the substratethrough a welded portionThe metal layermay be firmly fixed to the substrateso that the metal layeris not lifted from the tabeven when the substrateis bent. Accordingly, the metal layercan prevent a problem of decreased reliability due to substrate cracks occurring in the tab boundary portion between the taband the substrate.

240 210 210 240 210 240 240 210 210 Meanwhile, for example, the metal layermay include the same material as that included in the substrate. For example, when the substrateincludes aluminum as the positive electrode current collector, the metal layermay include aluminum, a metal coated with aluminum, aluminum coated with another material, or an alloy containing aluminum. In other embodiments, for example, when the substrateincludes copper as the negative electrode current collector, the metal layermay include copper, a metal coated with copper, copper coated with another material, or an alloy containing copper. In this way, since the metal layerincludes the same type of material as that of the substrate, it is possible to further improve weldability with the substrate.

240 210 210 210 240 However, the material included in the metal layermay include not only the same material as the material included in the substratebut also any material with good weldability with the material included in the substrate. For example, when the substrateincludes copper, the metal layermay include at least one of iron (Fe), stainless steel (SUS), nickel (Ni), gold (Au), silver (Ag), and a combination thereof, as a material with good weldability with copper.

200 210 With this structure, the electrodeaccording to an embodiment of the present disclosure can reinforce the strength of the substrateand/or improve the reliability thereof.

3 FIG. is a top view schematically showing an electrode according to an embodiment of the present disclosure.

3 FIG. 3 FIG. 230 230 In, an x-axis denotes a width direction of the tab. In addition, in, a z-axis denotes a longitudinal direction of the tab.

3 FIG. 1 2 FIGS.to 2 FIG. 3 FIG. 200 200 240 210 230 230 240 210 240 w In, an electrodeis shown (including, for example, the electrode described with respect to) according to an embodiment of the present disclosure. As described with respect to, the electrodemay include a metal layerprovided on the substratewhile covering the tab(e.g., while covering a portion of the tab). In, a welded portionjoining the substrateand the metal layerwill be described.

240 210 240 210 w The metal layeraccording to an embodiment of the present disclosure may be joined to the substrateby forming the welded portionthrough welding with the substrate. The welding may include, for example, laser welding, ultrasonic welding, and the like.

240 230 230 240 210 230 230 240 240 210 230 230 w w w The welded portionmay be spaced a predetermined distance from the taband formed parallel to the tab. The welded portionmay be formed to be spaced a predetermined distance apart from the tab boundary portion between the substrateand the tab. In this case, the predetermined distance may be 1 mm or more. When the predetermined distance is formed to be less than 1 mm, the tabmay be damaged as the welded portionis formed. Therefore, the metal layermay be firmly fixed to the substrateand/or the tabwhile preventing the tabfrom being damaged.

3 FIG. 240 230 230 210 240 230 230 210 230 240 210 w w In this case, for example, as shown in, the welded portionmay be formed to surround the tabalong a boundary between the taband the substrate. The welded portionmay be formed to surround the tabalong a boundary between the taband the substrate(e.g., along three sides of the tab, as viewed in a top view). Therefore, the metal layermay be more firmly joined to the substrate.

240 230 210 240 240 1 230 240 2 230 240 3 230 w w w w w In other embodiments, the welded portionmay be formed along a boundary between side surfaces and/or a bottom surface of the taband the substrate. For example, the welded portionmay include one or two selected from a left welded portionformed along a boundary of a left side of the tab, a right welded portionformed along a boundary of a right side of the tab, and a rear welded portionformed along a boundary of a rear side of the tab.

230 230 230 240 1 230 240 2 230 240 3 230 w w w In this case, the left side of the taband the right side of the tabmay refer to a left side and a right side of the tabalong the x-axis. Therefore, the left welded portionmay be a welded portion provided at the left side along the x-axis on a side surface of the tab. In addition, the right welded portionmay be a welded portion provided at the right side along the x-axis on a side surface of the tab. In this case, the rear welded portionmay be a welded portion provided at one side of the tabalong the z-axis direction.

240 Therefore, the metal layerwith improved process efficiency can be provided.

4 FIG. is a top view schematically showing an electrode according to an embodiment of the present disclosure.

4 FIG. 1 3 FIGS.to 240 In, metal layerof an electrode is shown (including, for example, the electrode described with respect to) according to an embodiment of the present disclosure.

240 210 240 210 w The metal layeraccording to an embodiment of the present disclosure may be joined to the substrateby forming the welded portionthrough welding with the substrate. The welding may include, for example, laser welding, ultrasonic welding, and the like.

240 230 230 w 5 FIG. The welded portion(see) may be spaced a predetermined distance from the taband formed parallel to the tab.

3 FIG. 240 240 1 240 2 240 3 240 240 4 w w w w w w For example, as described with respect to, the welded portionmay include at least one of the left welded portion, the right welded portion, and the rear welded portion. Furthermore, the welded portionmay further include an upper welded portion.

240 4 230 240 240 4 240 230 240 4 230 240 230 240 240 4 230 240 w w w w The upper welded portionmay be formed by directly joining the taband the metal layer. For example, the upper welded portionmay be formed by performing welding from an upper side of the metal layertoward the tab. That is, the upper welded portionmay be a welded portion that connects the taband the metal layerin a y-axis direction. For example, the taband the metal layermay be welded through the upper welded portionwhile reducing resistance dispersion that may occur during welding of the taband the metal layer.

240 240 1 240 2 240 3 240 4 240 230 w w w w w For example, the welded portionmay include at least one of the left welded portion, the right welded portion, the rear welded portion, and the upper welded portion. Therefore, the metal layermay be attached to the tabwhile reducing resistance dispersion.

5 FIG. 3 FIG. is a cross-sectional view taken along line A-A′ ofshowing an example of a metal layer according to an embodiment of the present disclosure.

5 FIG. 3 FIG. 5 FIG. 230 230 230 230 In, an x-axis denotes the width direction of the tabdescribed with respect to. In addition, in, a y-axis (e.g., straight into the page) denotes a height direction of the tab. In this case, the height direction of the tabis perpendicular to the width direction of the tab.

5 FIG. 2 4 FIGS.to 2 4 FIGS.to 240 200 240 210 230 In, reference numeraldenotes a metal layer (including, for example, the metal layer described with respect to) according to an embodiment of the present disclosure. As described with respect to, the electrodemay include the metal layerprovided on the substratewhile covering the tab.

240 240 240 230 240 230 230 230 240 230 210 230 210 As described above, the metal layermay include a metallic material. The metal layerhas relatively high rigidity compared to a polymer material in the form of a film, such as tape. The metal layermay be molded to correspond to a shape of the tab(e.g., the metal layermay be formed over the tabto trace the outer shape of the taband be continuously conformal over the tab). Accordingly, the metal layermay be joined with the taband the substratewhile coming into close contact therewith without forming any gap between the taband the substrate.

230 240 230 240 241 230 242 241 210 4 FIG. For example, in a cross-section perpendicular to the longitudinal direction of the tab, the metal layermay be formed to correspond to the shape of the tab. The metal layer(see) may include a tab cover layerprovided to surround the tab, and a substrate cover layerthat extends from the tab cover layerand is provided on the substrate.

241 241 230 241 1 230 241 2 230 241 230 230 u s s The tab cover layermay include an upper surface tab cover layerthat covers the upper surface of the tab, a left side surface tab cover layerthat covers the left side surface of the tab, and a right side surface tab cover layerthat covers the right side surface of the tab. The tab cover layermay protect the taband may be electrically connected to the tabat the same time.

241 230 241 241 230 230 230 241 1 241 2 230 230 210 241 230 230 241 230 s s u A shape of the tab cover layermay be formed to correspond to the shape of the tabcovered by the tab cover layer(e.g., the tab cover layermay be formed over the tabto trace the outer shape of the taband be continuously conformal over the tab). For example, when a distance between the left side surface tab cover layerand the right side surface tab cover layeris w, w may be formed as a width that is the same as or within the same range as a width in the width direction of the tab. In this case, the same range may include an error range that may occur during the manufacturing process of the tab. For example, the error range may be ±3%. In other embodiments, for example, when a distance from the substrateto the upper surface tab cover layeris h, h may be formed as a height that is the same as or within the same range as a height in the height direction of the tab. In this case, the same range may include an error range that may occur during the manufacturing process of the tab. For example, the error range may be ±3%. Therefore, the tab cover layermay be in close contact with the tab.

242 210 242 210 242 241 1 242 241 2 242 210 210 a s b s The substrate cover layermay be provided on an upper surface of the substrate. For example, the substrate cover layermay be provided on the substrate, and may include a left side surface cover layerthat is connected to the left side surface tab cover layerand a right side surface substrate cover layerthat is connected to the right side surface tab cover layer. The substrate cover layermay reinforce the substrateand may be electrically connected to the substrateat the same time.

241 242 240 210 240 230 210 240 230 240 210 210 210 200 240 210 In addition, the tab cover layerand the substrate cover layermay be electrically connected to each other. Therefore, the metal layermay provide a path through which electrons can move from the substratevia the metal layerto the tabeven when cracks occur in the substrate. In other embodiments, the metal layermay provide a path through which electrons can move from the tabvia the metal layerto the substrateeven when cracks occur in the substrate. Accordingly, when the substrateis bent along the electrode, the metal layermay be bent along the substrate.

240 230 240 230 210 240 240 210 In this way, the metal layermay be formed into a shape corresponding to the tabthrough excellent rigidity and formability, and may maintain the shape. Accordingly, the metal layermay prevent the tab boundary portion between the taband the substratefrom being exposed by the metal layer. Therefore, the metal layeraccording to an embodiment of the present disclosure can prevent a problem of decreased reliability due to cracks occurring in the substrate.

240 210 Furthermore, the metal layermay be joined to the substratethrough welding, thereby reducing process variation.

6 FIG. 3 FIG. is a cross-sectional view taken along line A-A′ ofshowing an example of a metal layer according to an embodiment of the present disclosure.

6 FIG. 1 5 FIGS.to 6 FIG. 200 240 200 40 In, an electrode(including, for example, the electrode described with respect to) is shown, according to an embodiment of the present disclosure. In, an example of the metal layerin a case where the electrodeincluded in the electrode assemblyis bent will be described.

1 5 FIGS.to 100 40 50 40 40 240 40 As described with respect to, the secondary batteryaccording to an embodiment of the present disclosure may include the electrode assemblyand the cylindrical casethat accommodates the electrode assembly. In this case, the electrode assemblymay be formed by being wound with a curvature. In addition, the metal layermay also be formed by being bent with a curvature that is the same as or similar to that of the electrode assembly.

40 40 200 40 40 200 40 210 40 For example, the electrode assemblymay be wound to form a jelly roll. The electrode assemblymay be bent with a curvature. Accordingly, the electrodeincluded in the electrode assemblymay be bent with the same curvature as that of the electrode assembly. For example, a radius of curvature of the electrodemay be r. In this case, 1/r denotes the curvature of the electrode assembly. For example, r denotes the shortest distance from an upper surface of the substrateto a winding center of the electrode assembly.

240 210 240 230 200 240 200 6 FIG. In this case, for example, the metal layermay be provided on the substratein a direction toward a winding center portion (for example, O in). The metal layermay be formed in the direction toward the winding center portion while covering the tab. Therefore, even when the electrodeexpands, the metal layercan receive less tensile force, thereby more effectively improving the reliability of the electrode.

7 FIG. is a top view schematically showing an electrode according to an embodiment of the present disclosure.

8 FIG. is a top view schematically showing an electrode according to an embodiment of the present disclosure.

9 FIG. is a top view schematically showing an electrode according to an embodiment of the present disclosure.

7 9 FIGS.to 1 6 FIGS.to 7 9 FIGS.to 7 240 FIG., 8 240 FIGS.and 9 FIG. 200 240 240 210 a b c In each of, an electrodeis shown (including, for example, the electrode described with respect to) according to an embodiment of the present disclosure. In, various embodiments of the metal layer(ininin) attached to the substratewill be described.

2 6 FIGS.to 240 210 230 As described with respect to, the metal layeraccording to an embodiment of the present disclosure may be provided on the substratewhile covering the tab.

7 FIG. 240 240 230 210 240 210 230 230 230 230 240 210 a a For example, as shown in, the metal layermay include a first metal layerthat covers the entire region of the tablocated on the substrate. The first metal layermay be provided on the substratewhile covering all of a left side surface of the tab, a right side surface of the tab, and a bottom surface of the tabconnecting the left side surface and right side surface of the tab. Accordingly, the metal layercan maximize the effect of reinforcing the strength of the substrateand preventing cracks from occurring in the tab boundary portion.

8 FIG. 240 240 230 210 240 210 230 230 230 230 210 230 210 230 230 230 240 b b b For example, as shown in, the metal layermay include a second metal layerthat covers a partial region of the tablocated on the substrate. The second metal layermay be provided on the substratewhile covering a portion of the left side surface of the tab, a portion of the right side surface of the tab, and the bottom surface of the tabconnecting the left side surface and right side surface of the tab. Cracks in the substrategenerally occur frequently in the tab boundary portion between the taband the substrate. In particular, there is a high probability of vertical or horizontal cracks occurring along a longitudinal direction (z-axis direction) of the tabor a width direction (x-axis direction) of the tabfrom a point at which the side surfaces and the bottom surface of the tabmeet. The second metal layercan reinforce a location at which the probability of occurrence of cracks is high.

9 FIG. 240 240 230 210 240 240 1 240 2 230 240 1 210 230 230 240 1 240 2 240 2 210 230 230 230 230 240 240 2 210 240 1 c c c c c c c c c c c For example, as shown in, the metal layermay include a plurality of the metal layerthat cover partial regions of the tablocated on the substrate. In this case, the metal layermay include a third upper metal layerlocated relatively higher and a third lower metal layerlocated relatively lower in the longitudinal direction (z-axis direction) of the tab. For example, the third upper metal layermay be provided on the substratewhile covering another portion of the left side surface of the taband another portion of the right side surface of the tab. The third upper metal layermay be positioned spaced apart from the third lower metal layer. The third lower metal layermay be provided on the substratewhile covering a portion of the left side surface of the tab, a portion of the right side surface of the tab, and the bottom surface of the tabconnecting the left side surface and the right side surface of the tab. In this way, the metal layercan reinforce a location at which the probability of occurrence of cracks is high through the third lower metal layerand further contribute to reinforcing the strength of the substratethrough the third upper metal layer.

240 240 210 230 7 9 FIGS.to The embodiments of the metal layerdescribed with respect toare merely examples. The metal layermay include a metallic material and may be applied in any form provided on the substratewhile covering at least a portion of the tab.

10 FIG. is a cross-sectional view schematically showing an electrode according to an embodiment of the present disclosure.

10 FIG. 1 9 FIGS.to 2 9 FIGS.to 200 200 240 210 230 In, an electrodeis shown (including, for example, the electrode described with respect to) according to an embodiment of the present disclosure. As described with respect to, the electrodemay include the metal layerprovided on the substratewhile covering the tab.

200 250 210 For example, the electrodemay further include an additional metal layerprovided on the other surface of the substrateand including a metallic material.

250 240 210 250 230 250 250 220 220 100 The additional metal layermay be provided on a opposite surface to the metal layerwith the substrateinterposed therebetween. For example, the additional metal layermay be provided on a surface on which the tabis not formed on the uncoated portion. In this case, the additional metal layermay not be formed on the coated portion. In this way, since the additional metal layeris provided so as not to come into contact with the coating layer, it is possible to prevent the problem of hindering the electron movement of the coating layerand reducing the capacity of the secondary battery.

250 210 210 250 210 250 250 210 210 250 210 The additional metal layermay include, for example, the same material as that of the substrate. For example, when the substrateincludes aluminum, the additional metal layermay include aluminum. For example, when the substrateincludes copper, the additional metal layermay include copper. In addition, the additional metal layermay be joined to the substratethrough, for example, a welded portion formed by welding on the substrate. In this way, the additional metal layercan improve the welding strength to the substrate by including the same material as that of the substrate.

250 210 210 With this configuration, the additional metal layeraccording to an embodiment of the present disclosure can further improve the strength of the substrateand prevent a problem of decreased reliability due to cracks occurring in the substrate.

11 FIG. is a cross-sectional view schematically showing an electrode according to an embodiment of the present disclosure.

12 FIG. is a cross-sectional view schematically showing an electrode according to an embodiment of the present disclosure.

11 12 FIGS.and 1 10 FIGS.to 2 10 FIGS.to 200 200 240 210 230 In, an electrodeis shown (including, for example, the electrode described with respect to) according to an embodiment of the present disclosure. As described with respect to, the electrodemay include the metal layerprovided on the substratewhile covering the tab.

200 260 210 230 The electrodemay further include an insulating tapeattached to the substratewhile covering the tab.

260 200 260 210 220 230 240 The insulating tapemay protect all or part of the components included in the electrodefrom the outside. For example, the insulating tapemay prevent the substrate, the coating layer, the tab, and/or the metal layerfrom being damaged by an external force or from being short-circuited by another electrode plate.

260 210 To this end, the insulating tapemay be attached to at least one surface of the substrate.

11 FIG. 260 210 260 210 240 260 210 240 230 For example, as shown in, the insulating tapemay be attached to one surface of the substrate. For example, the insulating tapemay be attached to the surface of the substrateon which the metal layeris provided. For example, the insulating tapemay be attached to the substratewhile covering the metal layer(which covers the tab).

12 FIG. 260 260 210 260 210 240 260 210 240 200 200 In other embodiments, for example, as shown in, insulating tapeand insulating tape′ may be attached to both surfaces of the substrate. For example, the insulating tapemay be attached to the surface of the substrateon which the metal layeris provided. In addition, for example, the insulating tape′ may be attached to the surface of the substrateon which the metal layeris not provided. Therefore, the electrodecan secure safety in relation to other electrodes and/or separators located on one side and the other side of the electrode.

260 210 230 240 260 260 220 260 200 In this case, for example, the insulating tapemay be attached to the uncoated portion and may be attached to the substrate, the tab, and/or the metal layer. Furthermore, the insulating tapemay also be attached to the coated portion. For example, the insulating tapemay be attached to the uncoated portion, and may cover the coating layerby extending from the uncoated portion toward the coated portion. Therefore, the insulating tapecan protect all or part of the components included in the electrodefrom the outside.

260 In addition, to this end, the insulating tapemay include an insulating material.

For example, the insulating material may include at least one of polyimide (PI), polysulfone, polyurethane (PU), polyamide (PA), 6,6 nylon, polycarbonate (PC), polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET).

260 210 220 230 240 Meanwhile, the insulating tapemay further include an adhesive material so that the insulating material is attached to the substrate, the coating layer, the tab, and/or the metal layerwith adhesiveness.

For example, the adhesive material may include at least one of a silicone resin, an acrylic resin, a urethane resin, a rubber resin, an epoxy resin, a polyolefin, and a combination thereof.

For example, the acrylic resin may include acrylic, an ester copolymer, ethyl acrylate, butyl acrylate, hexyl acrylate, n-octyl acrylate, iso-octyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, aryl acrylate, acrylic acid, maleic acid, fumaric acid, itaconic acid, kryptonic acid, acrylamide, N-vinyl pyrrolidone, N-vinyl caprolactam, acrylonitrile, acryloyl morpholine, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, and the like.

For example, the urethane resin may include polyurethane, etc.

For example, the rubber resin may include natural rubber, synthetic rubber, etc.

200 200 Therefore, the electrodeaccording to an embodiment of the present disclosure may provide a method of protecting each component included in the electrode.

200 250 210 250 9 FIG. Meanwhile, when the electrodefurther includes the additional metal layeras described with respect to, the insulating tape may be attached to the other surface of the substratewhile covering the additional metal layer.

When the secondary battery is charged, the electrode may expand. In this case, as the electrode is compressed by expansion, the substrate may be deformed. In particular, stress applied to the substrate may be concentrated in a tab boundary portion, which is a region where the tab is attached in the substrate. Accordingly, the tab boundary portion may reach a local elongation limit, and cracks may occur in the tab boundary portion.

In particular, recently, as higher capacity secondary batteries are required, the substrate tends to become thinner. Accordingly, cracks may occur more easily in the substrate.

When cracks occur in the electrode, the resistance of the secondary battery increases, heat generates around the cracks, and/or the capacity of the secondary battery decreases, thereby decreasing the reliability of the secondary battery.

An embodiment of the present disclosure relates to an electrode and/or a secondary battery that prevents (e.g., or minimizes) cracks from occurring in a substrate.

Another embodiment of the present disclosure relates to an electrode and/or a secondary battery that maintains electrical conductivity even when cracks occur in the substrate.

According to the present disclosure, an electrode and/or a secondary battery with improved reliability can be provided.

However, the effects that can be achieved through the present disclosure are not limited to the above-described effects, and other technical effects not mentioned will be clearly understood by those of ordinary skill in the art from the description of the disclosure described below.

Although the present disclosure has been described above with limited examples and drawings, the present disclosure is not limited thereto, and it is obvious that various modifications and variations may be made by those skilled in the art in the technical field to which the present disclosure belongs within the technical idea of the present disclosure and the equivalent scope of the patent claims described below.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described with respect to connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described with respect to connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.